There are 3 fans in my old desktop computer ie 2 fans to draw
out the hot air and 1 CPU fan. The noise made by the fans are
loud.
Are there any ways to reduce the noise level to a barely audible
level ?
Thanks for any advice.
1: check how the fans are connected. firstly, if the fans are
connected to your motherboard via 3-pin
or
4-pin fan connectors, you may use speedfan to try and lower the
speed of the fans. if that doesn't work, boot into your
motherboard's BIOS and see if you can lower the fan voltage from
there. sometimes the motherboard defaults it at the 12V maximum,
try lowering it to around 7V for the best blend of performance as
well as noise level.
2: if the fans connect via
molex, there's no way to control the speed, as it's running off
it's 12V max power. note how the pins are arranged in molex. there
are 4 wires on the molex plug. the yellow wire is the 12V
supply, right beside it is a black wire which is the grounding wire
for the 12V supply. on the other side there will be a red wire. the
red wire is for 5V, and the one next to it is it's grounding. if
you notice, the wires leading to the fan motor will be soldered to
the yellow and the black wire, meaning that it's on the 12v rails.
your current connection looks like this.
from
PSU:
fan
connector:
Red (5V) ----------------> Red (pass
thru)
Black (5V GND) ------> Black (pass thru)
Black (12V GND) ----> Black (black wire leading to fan)
Yellow (12V) -----------> Yellow (red wire leading to fan.)
here's a picture to show.
if you look carefully, you'll see how the fan is attached to the
yellow and black i mentioned about.
now, you want to reduce the noise, and to do this you've got to
slow the fan down.
ideally, you'll want it to run on just 5V.
so you unplug the fan from the power supply...
and plug it back in the other way. so now it'll look like this:
from
PSU:
fan
connector:
Red (5V) ----------------> Yellow
(red wire leading to fan.)
Black (5V GND) ------> Black (black wire leading to fan)
Black (12V GND) ----> Black (pass thru)
Yellow (12V) -----------> Red (pass thru)
this will make it run on 5V, which will effectively silence your
fans, but you're sacrificing some vital airflow for this
silence.
there's another way that you could squeeze 7V out of the fans,
but this modification is tricky, and stresses your power supply so
i won't say how to perform it here.
3: turn your pc off and remove the fan. clean out all the grime
on the fan if it's really dirty. give the fan a slight spin with
your finger. does it spin freely and smoothly? if not, this means
the fan bearings are dry.
on the motor side of the fan (where the wires enter) there will
be a sticker over the hub. peel it off to reveal the rubber cap
over the bearing - keep the sticker as you'll need it
still. remove the rubber cap, and drip some oil into it. best
choice would be mineral oil, but motor oil as well as regular
singer oil will suffice. don't use WD40, since it will just dry up
the bearings again. don't fill the oil well to it's brim - the
oil will spill out when the fan turns or when you replace the cap.
replace the rubber cap carefully and place the sticker over it
again. let the fan sit sticker side up for about an hour, then plug
the fan in again and run it for awhile to let the oil lubricate the
bearings.
